The invention is directed to improvements in valves for fuel injection systems of internal combustion engines. From German Patent Disclosure Document DE 38 31 196 A1, a valve is already known in which an adjusting sheath is forced into a spring chamber opening, and a restoring spring acting upon the valve closing part is supported on this sheath, the depth of insertion into the spring chamber opening determines the spring force of the restoring spring. When the adjusting sheath is pressed in, the danger exists that chips will be formed at the adjusting sheath and at the wall of the spring chamber opening, thereby soiling and possibly damaging the valve because of the metal chips.